Improvement in furnaces



UNITED STATES PATENT Orrtcn.

THOMAS ALDRIDGE AND JOHN ALDRIDGE, OF HUDSON, NEV JERSEY.'

IMPROVEMENT IN FURNACES.

Specification forming part of Letters Patent No. 18,491, dated October `27, 1857.

To all whom t may concern:

State of New Jersey, have made certain new` and useful improvements in the arrangement of furnaces for burning the Waste smoke and gases, and at the same time supplying such furnaces with a hot-air blast, thus yrendering all such a smokeconsuming hot-air-blast furnace; and We do hereby declare that the following is a full and clear and exact description of the construction and operation of the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon and making a part of this specification.

Figure l is a general perspective View of an ordinary boiler and furnace with our invention attached thereto, and showing how it is made self-regulating or automatic by and according to any desired pressure of the steam. Fig. 2 isa more particular View of the mechanical arrangement by which our invention is rendered self-adjusting or automatic, and which is worked by the pressure of the steam in the boiler.

The nature and objects of our invention consist in the application and use of new and improved mechanism by which the smoke and gases that generally pass olf through the chimney and are lost are Withdrawn from the chimney,mixed With heatedatmospheric air to promote their entire combustion, and then carried to and under and consumed by the fire, thereby economizng fuel and obtaining an increased quantity of heat therefrom, and also in rendering the entire apparatus a mechanism self-regulating or automatic.

In the various methods which have been heretofore devised for burning the smoke of furnaces the effort has usuall7 been to coniine the smoke ou top of the tire, thus rendering the furnace a close furnace, and consequently rendering necessary some means to facilitate combustion, retarded by the pressure of the smoke on top, and Which also would check or interfere With the natural and necessary draft of the tire. These obj ections are obviated by our invention, While the combustion of the smoke is more complete, `and the draft is rendered more uniform, and is also made selfregulatin g.

refgrate.

Its construction and operation are as follows:

A is an ordinary cylinder-boiler set in the foundation B, the chimney O being in this case represented a little at one side of the rear end ot' the boiler.

D is the furnace-door, and E. the door to the ash-pit underneath the lire. These are constructed as usual.

To the chimney at or near the point or place` at which the smoke, the., enter' it or cease to act upon the boilers, We attach or insert a tube or smoke-conductor F, the other end of which enters the ash-pit or under the This conductor is all close except at the ends, and maybe constructed of Wood or brick; but it should be constructed of materials which are the poorest conductors of heat. If made of other materials, it can be covered with any non-conductor. It may also be connected at eitherside of the chimney or smoke-stack, most convenient in any particular case; but it is preferable to connect it to that side opposite or nearest opposite to the fire, as then the natural current of the smoke, heat, duc., will co-operate With any mechanical means made use of to take these from the chimney. Such conductor may of course be accommodated in shape, direction, &G.,to the circumstances of any particular case,though sharp turns in it should be avoided; but it should be connected with the chimney near Where the smoke enters it, or when the boilers extend only a part of the distance to the chimney and there is a flue between them and the chimney, then it should be connected to such iiue at or near the point Where the smoke and gases cease to affect the boilers, and the other end should enter the furnace under the fire, as these are the most iniportant requisites of its position.

To the smoke-conductor We attach a blower G, the exact location of which in the conductor is not material, except that it should be near the chimney to draw more completely the smoke, ctc., from the chimney and more perfectly mix therewith the atmospheric air for the purposes hereinafter stated. Its construction is not peculiar, except thatit has its discharge-opening at the side, experience having shown that when so constructed its capacity of discharge is increased. XVe actu ally, as a general thing, construct the blower with an opening ou each side, so that according to location the conductor may be attached to either side of it, and so that when desired a conductor may lead from each side to a separate iire or furnace, thus at the same time supplying a hot-air blast to two or'more fires. Its size should be proportioned tothe amount of fuel consumed and to the size of the furnace or engine. Its action is to cause a constant suction or draft from the chimney, thus preventing the escape and loss of the smoke, &c., and forcing it in the direction of the arrow under the tire, in passing through which everything of a combustible nature is consumed, thus increasing heat and economizing fuel.

In the construction of new furnaces, or when the same can be done in altering old ones, it will be best to place that part of the conductor F between the blower and the furnace within the foundation and under the boilers and opening under the fire through the bridge-wall, so that there shall be but little, if any, loss ofheat, or which does not act upon the boilers.

As is well known, the combustion of fuel, particularly coal, produces large quantities of carbonio-acid gas, to get rid of which, as it is not a supporterof combustion,has been an end much sought for. This, however, We do not so much desire to accomplish as to supply and mix therewith large quantities of heated atmospheric air to increase combustion. of gases being, however, a mechanical mixture rather than a chemical affinity or combination, it becomes necessary that the smoke, &c., drawn from the chimney should be effectually mixed with the atmospheric air and that this mingling should be effected before the parts are brought in contact with the iire. This we accomplish by admitting atmospheric air into the smoke-conductor near the blower or between it and the chimney, so that both together shall be subjected to the action of the blower, by which they are completely mixed, and by which, also, an abundant supply of atmospheric air is obtained. In order, however, that the tire may not be checked-by the temperature of the atmospheric air, the pipe which supplies it should be so situated in respect to the fire or boilers that the air will be heated before it passes into the conductor, as above described.

In the drawings, H is the mouth of the atmospheric-air tube, and its position and its entrance into the smokeconductor F is shown by dotted lines 7L 7L. As the quantity of atmospheric air required will of course vary somewhat, according to the kind of coal burned, the admission of the air is regulated by the slide-door I, by which the mouth of the tube H may be enlarged or diminished, as desired. The furnace and ash-pit doors should be shut tightly, so that no air can enter the furnace except from F. As above remarked, the posit-ion of the tube H or the location of The union its mouth opening to the atmosphere is immaterial, it only being important that it should be so placed in respect to the [ire or boiler that the air can be completely heated and that the other end connects with the smokeconductor at or behind the blower.

As will be apparent from the foregoing description, the draft of the fire will depend upon or, rather, is produced by the blower, which forces the smoke and gases under and through the fire, and is not produced or affected to any extent oy the form or height of the chimney, the expense of constructing which and lining it with tire-brick can be saved.

To render our invention automatic, we regulate the speed of the blower, and consequently the draft of the re, by and according to any required pressure of the steam in the boiler. This we accomplish bythe following arrangement: From the boiler A a steam-pipe J connects with and under a small cylinder K,

which may be placed where most convenient or desirable, in which plays a piston or iioat having a rod L, such float beinga little smaller than the cylinder, so that there shall be but little or no friction,and resting upon asti-ong piece of vulcanized rubber fastened between the sides and bottom flange of the cylinder, and which will from its elasticity allow all necessary movement to the float and its rod. Upon L rests the lever M, the short arm having its fulcrum at N and the long arm regulated by the weightlV, so that the oat will move at any desired pressure of steam in the boiler. To this long arm connects the elbow or bent lever P by means of the short bar O,

the elbow P working on the pivot p, and the other end of which joints with the strap-stick a a ct a, which plays between the conical pulleys Q Q', changing the position of the band b b,the links c c moving such band more certainly and quickly. These conical pulleys are placed so that the largest diameter of one shall be opposite to the smallest diameter of the other, one Q having a fast-and-loose pulley d, as it is called, over which plays a belt from the engine or any other power, and the other Q" working the blower G by means of a belt R. lVhenever the pressure of the steam becomes greater than that required, the long arm of the lever M will rise and through the elbow P move the strap-stick a, a in such a direction that the band I) will be moved to a smaller diameter of Q and to a larger di'- ameter of Q', thus decreasing the speed of the blower G, and consequently lessening the draft. lVhen the pressure becomes too little, the lever M will fall and the band b be moved in a contrary direction by a contrary movement of the strap-stick and the speed of the blower, and consequently the draft, be vincreased. Thus the act-ion of the blower and the draft is rendered automatic and is regulated wholly by the pressure of the steam, the draft increasing as the pressure of steam diminishes, and vice versa. In actual use this mechanical arrangement is continually vibrating, thus evidencing its sensitiveness and accuracy. In the drawings the strapstick and pulleys are represented as supported by the standards ffff; but they will be vusually supported from some part of the building overhead. i

The practical operation of our invention will be best illustrated .from the following facts: Ve constantlykeep the damper of our chimney almost entirely closed, nor is dense smoke, even when burning soft coal, ever seen to rise from it.

Previous to the use of our invention the brick-Work under our boilers became ,but moderately heated, while the chimney for some distance was made very hot, as is the case i-n common furnaces and chimneys; but now with its use the chimney becomes only moderately heated, while the foundation brick-work is constantly very hot, thus showing that the heat is retained and made effective where it should be-under the boilers. The temperature of the contents of the smokeconductor near Where it enters under the iire is also continually from 220O to 2300.

XVe are aware that smoke-consuming furnaces, as they are called, and We use the word smoke in its usual and broader signification, and not in its chemical and more restricted meaning, have been arranged; but in these as a general thing, and this We believe is particularly the case in those which have proved most available, the leffort has been to confine and retain by pressure or otherwise the smoke over the fire until it should be consumed. This is the case in the original and reissued patents of 1839 and 18525 of Diempfel, and also in Case and Soules patent of 1856, and is also the substantial arrangement made use of in Voodcocks English invention and patent, which seems to be the most successful in use there. The introduction of heated atmospheric air to assist combustion of the smoke has also been used; but the object of its introduction has been to produce and keep up the necessary combustion in the tire, which is of course checked and interfered with by obstructing the natural draft by means of the smoke confined on top of the fire; and by none of these plans has the combustion of the smoke been made to assist or influence the draft of the tire; nor have they been made self-regulating or automatic, both of which are united in our invention; nor can any of the most available plans, so far as We know, be attached to any ordinary boiler or furnace without material alterations for such purpose, Whereas our invention can be connected to any and all Without any necessityof changing their structure and at a tritling expense and With most satisfactory results. XVe do not therefore claim, generally, either the construction of smokeconsuming furnaces, as they are called, or returning the smoke, gases, sc., of the iire back to or under the lire or furnace, many differently-arranged plans having Vbeen devised and used for such purpose; nor do we claim the mingling of atmospheric air with the products of combustion, as this has been etlected to a greater or less degree by many inventions; but

What we claim as our invention, and desire to secure by Letters Patent, is-

l. The combination and arrangement of the smoke and gas conductor F, the atmosphericair tube H, and the blower G, arranged and located substantially as and upon the principles before declared, and for the uses and purposes set forth and described.

2. In connection with such arrangement of the smoke-conductor F and air-tube H, regulating the velocity of the blower G by and according to the pressure of the steam in the boiler through the intervention of the conical pulleys or their equivalent, substantially as and for the purposes set forth and described. ""-l THOMAS ALDRDGE.

JOHN ALDRIDGE. llitnesses:

ALFRED MCINTIRE, S. D. LAW. 

